(1) Field of the Invention
The present invention generally relates to a microwave oven which cooks food utilizing microwave frequencies produced by a magnetron. More particularly, it relates to a microwave oven which has a door of improved structure for opening and closing a cooking chamber of the microwave oven.
(2) Description of the Prior Art
Generally, a microwave oven is a cooking appliance which cooks food by frictional heat generated by making the molecules of the food being cooked move at high speeds utilizing high frequency energy.
FIG. 3 is a sectional view of the overall construction of a conventional microwave oven. As shown in the drawing, the conventional microwave oven includes a main body 10, a cooking chamber 20 and an electrical component compartment 30, both provided to the interior of the main body 10. The cooking chamber 20 of the main body 10 has an open side, and a door 40 is hinged on a front panel 10a of the main body 10 along one edge of the opening for opening and closing the open side of the cooking chamber 20. A latch member 41 is formed on a rear side of the door 40 facing the main body 10, the latch member 41 corresponding to a latch lock assembly 43 provided on the front panel 10a of the main body 10. The latch member 41 locks within the latch lock assembly 43 to firmly secure the door 40 in a closed position, and is unlocked by user manipulation of a release member 45, provided to one side of the door 40 when the same is closed.
The electrical component compartment 30 is provided to one side of the cooking chamber 20. In the electrical component compartment 30 are formed a magnetron 31 for producing high frequency energy and providing the same to the cooking chamber 20, a high voltage transformer 32 applying high voltage across the magnetron 31, and a fan 33 for cooling the electrical components during operation. A control panel 34 is mounted to one side of the closed door 40. Reference numerals 21 and 42 designate a disk-shaped tray and a window, respectively, the window formed on a middle portion of the door 40 to let a user see the inside of the cooking chamber 20 during operation of the microwave oven.
In the conventional microwave oven, if a user operates the control panel 34 after placing foodstuff on the tray 21 of the cooking chamber 20 and closing the door 40, the magnetron 31, provided in the electrical component compartment 30, supplies microwave frequencies of 2,450 MHz to the cooking chamber 20. The microwave frequencies make the molecules of the food being cooked move at high speeds, thereby cooking or heating the food.
However, in the microwave oven structured as in the above, it is possible for the microwave frequencies provided to the cooking chamber 20 by the magnetron 31 to leak out of the cooking chamber 20 through a gap between the door 40 and the main body 10. This leakage of microwave frequencies, even if it is slight, can interfere with other electronic devices and is harmful to humans. Therefore, laws strictly regulate manufacturing standards to allow only a minimal level of microwave frequency leakage.
Accordingly, as shown in FIG. 4, prior art microwave ovens include a choke assembly 50 provided on the door 40 for inhibiting microwave frequency leakage (FIG. 4 depicts the door 40 contacting the front panel 10a of the main body 10 when the door 40 is closed) . The choke assembly 50 includes a choke groove 51 formed on the rear side of the door 40, and a seal 52 made by injection-molding using a plastic material. The seal 52 closes an opening of the choke groove 51. Accordingly, the microwave frequencies are prevented from leaking out of the cooking chamber 20 by entering the choke groove 51 via its opening, and being mutually offset and compensated therein, thus eliminating microwave frequency leakage.
However, high frequencies having a short wavelength are created inside the choke assembly 50, and these may easily leak out through small gaps due to their short wavelength. If the front panel 10a of the main body 10 and the rear side of the door 40 are not formed flat, a large gap is created therebetween, thus causing an increase in the amount of high frequencies that leak out of the microwave oven. Thus, there is a limit to the prevention of high frequency leakage by the use of the choke groove 51 formed on the door 40.